The present invention relates generally to luminaires and, more particularly, to three-dimensional reflectors for such luminaires to produce a light distribution pattern in an area to be illuminated, and its method of manufacture.
Luminaires are designed to produce a predetermined light distribution pattern in an area to be illuminated, such as in parking lots, along roadways, or in other areas requiring broad illumination of a surface. Luminaires generally include a housing or enclosure that supports a light socket, a high-intensity light source mounted in the socket, a light reflector mounted behind and/or around the light source and other electrical hardware necessary to energize the light source. The illumination pattern created by the luminaire is generally defined by the shape of the light reflector mounted in the luminaire, as well as the position of the light source relative to the reflector. The reflector may form a partial enclosure about the source of light so that the inner surfaces of the reflector direct reflected light through an opening formed in a lower portion of the luminaire housing.
In the past, one-piece reflectors have been fabricated by molding or otherwise forming a flat piece of metal or other suitable reflective material into a desired reflector shape. The reflector may be formed by forming a sheet of reflective material between male and female dies that have cooperating three-dimensional shapes defining the reflector shape. Alternatively, the reflector may be formed by hydroforming the sheet of reflective material over a three-dimensional male form that defines the reflector shape as is well known in the art. In another method, the reflector may be spun by contouring a sheet of reflective material over a revolving male mandrel with a pressure tool to conform the sheet to the shape of the mandrel. In yet another method of fabricating reflectors, the sheet of reflective material may be formed using a press brake or other forming machine that successively bends the sheet along predetermined fold lines into a series of planar facets that approximate a desired curved surface of the reflector.
Reflectors have also been fabricated from multiple sheets of reflective material that have been individually shaped and formed and then assembled together to form a reflector shape. The individual parts of the multi-component reflector have either been joined together through fastening hardware or other suitable structures prior to mounting the assembled reflector in a luminaire housing, or the reflector components have been mounted individually within the luminaire housing to form the three-dimensional reflector shape within the housing.
Forming the desired reflector shape using cooperating male and female dies has a drawback that the dies are relatively expensive to make and are difficult to modify if changes in the reflector shape are required. Moreover, the sheet of material may not draw easily and consistently to achieve the necessary depth and shape of the reflector during deep drawing formations. Hydroforming or spinning of reflectors have the disadvantage that most reflector manufacturers do not have hydroforming or spinning capabilities in-house and must rely on outside contractors with that capability to form the reflectors. Another disadvantage of reflectors machine-formed into three-dimensional curved shapes, as by die-drawing, hydroforming or spinning, is that the reflective finish on the reflector must be applied in secondary operations, usually by polishing and anodizing. Using a press brake to successively bend the sheet of material has the drawback that many manufacturing steps or forming operations are required to form the many planar facets that define the reflector shape. Additionally, the series of planar facets formed by press brake forming operations do not provide a substantially continuous curve on the inner reflective surfaces of the sheet panels that may be required to create a certain light distribution pattern. It will also be appreciated by those skilled in the art that after reflectors are formed into their three-dimensional shapes through the methods above, significant warehouse space may be required to store the many reflector shapes that may be used. Lastly, multi-part reflectors suffer from the disadvantage that they may require storage and inventory of many different reflector parts and fastening hardware, as well as significant off-line subassembly prior to final fabrication of the three-dimensional reflector.
Thus, there is a need for a self-standing reflector and method of making same that allows the reflector to be formed relatively easily and consistently from at least one sheet of reflective material.
There is also a need for a self-standing reflector and method of making that allows the reflector to be rapidly formed from at least one sheet of reflective material in relatively few manufacturing steps or forming operations.
There is also a need for a self-standing reflector and method of making same that allows the reflector to be formed from at least one sheet of reflective material relatively quickly as needed at the time and place of luminaire fabrication, thereby reducing the warehouse space necessary to store many different reflector shapes.
There is yet also a need for a self-standing reflector and method of making same that allows the reflector to be formed from at least one sheet of reflective material with substantially continuous curves on the inner reflective surfaces of the reflector and retained in a predetermined three-dimensional shape.
The present invention overcomes the foregoing and other shortcomings and drawbacks of luminaire reflectors and methods heretofore known. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. On the contrary, the invention includes all alternatives, modifications and equivalents as may be included within the spirit and scope of the present invention.
In accordance with the principles of the present invention, a self-standing reflector and method of making same is provided for forming a reflector from at least one sheet of reflective material. Each sheet of material is preferably formed in a single hit die press to form a series of integral reflective panels. The sheets of reflective material are adapted to be joined together so that the panels may be folded by hand into edge-abutting relationship to define a predetermined three-dimensional reflector shape. At least some of the panels may include substantially non-linear free edges that abut substantially non-linear free edges of abutting panels. Each sheet of material is relatively thin to allow one or more of the panels to be curved by hand to define curved reflective surfaces. In this way, the abutting curved panels form a substantially contiguous curved reflective surface within the reflector.
The panels are preferably joined to adjacent panels through perforated fold lines that preferably include a series of elongated slots formed through the thickness of the sheet. The fold lines are perforated to allow the sheet of material to be easily folded by hand along the fold line to form the desired three-dimensional reflector shape.
Alternatively, a backing member made of relatively stiff sheet material may be attached to or otherwise operatively engaged with the sheet of reflective material. The backing member and sheet are positioned relative to each other so that at least one elongated edge of the backing member is coincident with a predetermined fold line in the sheet. Upon folding of a panel by hand, the edge of the backing member defines a consistent line of bending in the sheet along the predetermined fold line.
In an alternative embodiment of the present invention, elongated notches are provided in the sheet to define at least one generally narrow connecting web associated with at least one of the panels. The connecting web defines a consistent line of bending in the sheet that is coincident with a predetermined fold line.
The panels may include locking members formed proximate the panel edges that cooperate to provide locking engagement between abutting panel edges for retaining the reflector in its three-dimensional reflector shape. The locking members may include a locking tab extending from one panel edge that is inserted into a locking slot formed adjacent an abutting panel edge to form a locking engagement between the abutting panels. Positioning tabs may be formed to extend outwardly from free edges of the panels. The positioning tabs of one panel overlie an abutting panel to maintain abutting relationship of the abutting panel edges.
Thus, it will be appreciated that the reflector of the present invention may be fabricated in one or more hits in a die press that is relatively easy to modify in the event changes in the reflector shape are required. The reflector may be stored flat until needed, and readily assembled by hand for installation in a luminaire at the time and place of luminaire assembly, thereby requiring less warehouse space to store the various reflector shapes than would be required for storing pre-formed three-dimensional reflectors. It will also be appreciated that the reflector of the present invention provides a three-dimensional reflector shape that may be easily and consistently formed from at least one sheet of reflective material without a press brake or similar forming machine.
The above and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.